[Activity of urease in microcapsules].

The activity of urease in microcapsules formed by a symplex membrane from cellulose sulphate and polydimethyldiallyl ammonium chloride is studied and compared with that of free urease in solution. Both free and encapsulated urease exhibits a similar pH optimum. The interaction of urease with cellulose sulphate causes a decrease of the activity down to 35 to 38%.

[The interaction of methemoglobin and modified poly-(hydroxyethylmethacrylates) studied by spectroscopic methods].

The interaction between methemoglobin (MetHb) and macroporous matrices on the basis of polymethacrylates was investigated by means of optical and e.p.r.

Aspects of application of cytochrome P-450 and related systems in substrate hydroxylation.

Extrapolating the recent progress in the near future the extensive utilization of cofactor-dependent enzymes (enzymes of the 3rd generation) for solving economic or medical problems will be restricted by the difficulties of cofactor regeneration. Real possibilities exist in analytical systems, for instance enzyme electrodes. In the present paper a special case of overcoming the cofactor regeneration in P-450 catalyzed substrate hydroxylation is demonstrated: The peroxide-dependent reaction gives the same products as obtained under physiological conditions; that is why in an electro-enzyme-reactor producing hydrogen peroxide by cathodic oxygen reduction a considerable simplification of the multi-enzyme complex is possible by omitting electron transfer proteins.

Effect of protein-protein interactions on binding of ligands by proteins.

In general, saturation curves for ligand binding by proteins are described by the Adair-equation. The approach to ligand binding with methods of statistical mechanics leads not only to expressions for the Adair-constants, but gives also the possibility of describing the effect of protein-protein interactions on the binding of ligands by proteins. Under the assumption of the superposition-approximation for the potential of mean force between proteins in a solution, which contains also ligand molecules, the variations of the second and third virial coefficient with ligand activity are calculated for several simple model-pontentials.

[Molecular and complex-chemical studies on methemoglobin from Chironomus thummi thummi and various isolated fractions].

1. Six different hemoglobin (Hb) fractions were isolated and characterized from the larvae of Chironomus thummi thummi using column chromatographic procedures. 2.